The present invention relates to an improved device and process for making coffee and espresso (sometimes called "expresso") beverages or other hot beverages, and more particularly, but not exclusively, to an improved device and process for making coffee, tea, espresso coffee, and the like for individual servings in a microwave oven.
In the beverage industry, the espresso process involves forcing hot water or steam under pressure through a particulate substance. The general method of making espresso coffee is well known. It involves the process or method of forcing hot water or steam through conventional coffee grounds or some extra fine coffee grounds. This pressure method for making coffee differs significantly from the common methods for making drip-type or percolation coffees. The espresso coffee may be brewed with a mixture of espresso coffee grounds and cinnamon or other flavored syrups such as almond, orange, hazelnut, chocolate and the like. Espresso coffee generally is a dark full-bodied brew and may also be served as cappucino, caffe latte, caffe Americano, doppio, or macchiato.
Microwave ovens are widely used and known for a variety of heating tasks, including the heating of water for instant beverages or heating other beverages and foods. In addition, several devices have been proposed for brewing coffee in microwave ovens. Several devices and processes are described in the related patent applications identified above and incorporated herein by reference.
U.S. Pat. No. 5,281,785, issued Jan. 25, 1994 (Pasbrig), discloses a device for preparing coffee or tea in a microwave oven. The device has a liquid container, a centrally-located coffee container/filter, a drink container, and a handle. The path of the pressurized heated liquid is from the closed liquid container up through the coffee container/filter into the drink container.
U.S. Pat. No. 3,757,670, issued on Sep. 11, 1973 (Laama et al), discloses a two vessel electric coffeemaker wherein water is forced from the lower metal vessel through a centrally-located coffee container to the upper metal vessel so that the percolate is collected in the upper vessel. Laama et al uses an electrical heating element integrally constructed in the base of the device.
U.S. Pat. No. 4,498,375, issued on Feb. 12, 1985 (Bedini), discloses an automatic coffeepot in which the pressurized, heated liquid is forced up through a coffee-containing filter in a manner similar to Laama et al. Bedini uses a gas flame or electric heating coil for heating the coffeemaker.
U.S. Pat. No. 4,642,443, issued on Feb. 10, 1987 (Jorgensen et al), discloses a coffee brewing appliance for making coffee by the percolation method in a microwave oven. U.S. Pat. No. 5,079,396, issued on Jan. 7, 1992 (Katz et al), also discloses a microwave coffee percolating device. These devices disclose a percolating or drip-type technique for making coffee.
U.S. Pat. No. 4,104,957, issued Aug. 8, 1978 (Freedman et al), discloses a coffee brewing appliance comprising a carafe, a filter that fits in the neck of the carafe, and a water reservoir located over the filter. The water reservoir communicates with the filter by way of a thermally-controlled valve. When water in the water reservoir is heated by microwave radiation, the valve opens, allowing the water to flow into the filter, extracting coffee constituents from coffee grounds in the filter, so that a coffee beverage accumulates in the carafe.
U.S. Pat. No. 4,577,080, issued Mar. 18, 1986 (Grossman), discloses an appliance similar to that of Freedman et al, except that instead of using a thermally-controlled valve to prevent cold water from the water reservoir from contacting coffee grounds in a filter, a body of non-toxic wax melts when the water reaches the desired temperature.
U.S. Pat. No. 4,721,835, issued Jan. 26, 1988 (Welker), discloses a device for brewing coffee in a microwave oven. The device comprises a jug having a top configured as a filter. Water and coffee grounds are placed in the jug, and the filter is fitted in the mouth of the jug. When the coffee has brewed, it can be poured from the jug, while the coffee grounds are retained by the filter.
U.S. Pat. No. 4,386,109, issued May 31, 1983 (Bowen et al), discloses an espresso coffee maker for use in a microwave oven. The water is stored in a microwave transparent reservoir which is adjacent to an aluminum pot. The pot and reservoir are coupled in a fixed spatial relationship by a collar. The collar includes a strainer which presses against a layer of coffee grounds when the collar is secured to the reservoir. The compressed coffee grounds in combination with the strainer for a pressure resistant seal over the opening of the reservoir. The water in the reservoir is heated by microwave energy. The pressure rises to a level sufficient to force steam and water in a downward direction through the coffee grounds into the pot, which stores the espresso coffee.
U.S. Pat. No. 4,381,696, issued May 3, 1983 (Koral), discloses a coffee brewing appliance that is generally similar to that disclosed by Freedman et al.
U.S. Pat. No. 4,345,512, issued Aug. 24, 1982 (Moore), discloses a tea infuser for use in a microwave oven. The tea infuser, instead of being made of metal, is made of microwave-transparent plastic material.
U.S. Pat. No. 5,012,059, issued Apr. 30, 1991 (Boatman), discloses a device for heating water in a microwave oven. In Boatman's device, water is heated in a water reservoir, then forced from the water reservoir through a tube into a heating chamber, where it is further heated prior to draining through a filter filled with coffee grounds.
U.S. Pat. No. 4,990,734, issued Feb. 5, 1991 (Hirsch et al), discloses a method of preparing coffee where a mixture of water and coffee grounds is heated with microwave radiation, whereby a pressure gradient is produced across a filter, forcing filtrate into a vessel.
German No. OS 3,206,803 includes, seated one on the other, a coffeepot, a filter to receive coffee, and a water container. The water container is pervious to microwave radiation and the filter is developed so that substantially no liquid can pass through the filter under atmospheric or ambient pressure. The device is placed in a microwave oven in which the microwave radiation brings the water in the water container to a boil, while the coffee remains screened off. The formation of steam develops such a high pressure in the water container (up to 3.45 bar) that the water is forced through the filter.